This invention relates to electron multipliers, and particularly to a multiplier structure which includes a periodic nonplanar structure for confining the flow of electrons therethrough.
Display devices have been proposed in which electron multipliers operated in a feedback mode are used to provide current to light up a cathodoluminescent screen. For example, see U.S. Pat. No. 3,904,923 entitled "CATHODOLUMINESCENT DISPLAY PANEL." issued Sept. 9, 1975 to J. Schwartz. In one such structure, the electron multiplier includes at least two vanes having a plurality of parallel dynodes disposed in staggered relation thereon with a cathode at one end. This structure is further described in copending application of Ser. No. 672,122, filed Mar. 31, 1976, entitled, "PARALLEL VANE STRUCTURE FOR A FLAT DISPLAY DEVICE." In this structure, electrical potentials of increasing magnitude are provided to the successive multiplying dynodes so as to produce an electron beam at the multiplier output. Generally, the electron multiplier has an open structure to allow feedback of ions which results in sufficiently high loop gain to produce sustained electron emission.
A requirement of such a display is that the electron beam be confined to an area of the screen which is no larger than one picture element. Typically, the largest dimension of such an element is of the order of the width of a single dynode. However, in the previously described electron multipliers, spreading of the electron beam occurs in the direction along the length of the dynodes. This spreading is caused by nonzero secondary electron energies. Typically, this spreading, at normal operating voltages, results in an output beam size which is substantially larger than the dynode width and, hence, undesirable. Thus, it would be desirable to develop a multiplier design in which the electron beam is confined to a narrow length along the length of the dynodes as it traverses the dynodes.